1. Field of the Invention
The present invention relates to an evaluation method for evaluating the remaining strength of an installed pipe, a measurement device to be used in the evaluation method, and a pipe evaluation system using the measurement device.
2. Disclosure of Related Art
Agricultural pipelines and sewerage pipelines that are laid underground include a large number of pipelines that have been laid underground for a long time. Such pipelines are often routed under roads and buildings, and thus, it is difficult to dig those pipes and lay new pipes. Therefore, in general, with respect to these pipelines, the remaining strength of the pipe is evaluated in a state where the pipe is buried in the soil, and then, the pipe is subjected to repair or reinforcement in accordance with the result of the evaluation. Japanese Laid-Open Patent Publication No. 2004-28976 describes a technique of evaluating the remaining strength of a pipe through an impact elastic wave test.
As mentioned above, the remaining strength of a pipe is usually evaluated in a state where the pipe is buried in the soil. However, with the technique described in Japanese Laid-Open Patent Publication No. 2004-28976, it is difficult to accurately evaluate the remaining strength of a pipe in a state where the pipe is buried in the soil, due to the influence of the ground surrounding the pipe. Therefore, conventionally, the state of the inside of the pipe is confirmed through visual observation to roughly evaluate the remaining strength of the pipe, and then, a construction method for repair and reinforcement is determined. Therefore, in order to ensure the safety, excessive repair or reinforcement of the pipe tends to be performed, thus causing problems such as increased cost and a prolonged construction period.